(a) Field of the Invention
The present invention relate to a method and apparatus for scheduling data transmission of terminals in WLAN and WPAN environments.
(b) Description of the Related Art
In a wireless communication system such as WLAN (wireless local area network) or WPAN (wireless personal area network), a control station such as an AP (access point) or a PNC (piconet cordinator) allocates a chance for transmission to terminals according to a predetermined policy in a predetermined time period so as to enable the terminals to transmit data without depending on a competitive way.
For example, an AP of WLAN classifies time periods into competitive periods and noncompetitive periods and gives an exclusive chance for transmission to a specific terminal in a noncompetitive period by using a polling method. That is, if the AP occupies a channel with the highest priority for resource allocation and transmits a polling message to terminals, a terminal selected in advance starts to transmit data immediately upon receiving the polling message.
In such a general resource allocation method, during one chance for transmission, one terminal is exclusively given a chance for transmission. However, since a terminal having a highly-directional transmission capacity or reception capacity forms a narrow beam, even when the terminal is transmitting or receiving data, other terminals that are not in the zone of the beam can perform data transmission/reception without interfere with each other.
Nevertheless, since a wireless communication system according to the related art gives a chance for transmission to only one terminal pair in the same time period during resource allocation based on a noncompetitive method, it is not utilizing a merit of a terminal having a highly-directional transmission/reception capacity as it should.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.